With the recent development of networks, a mobile terminal can be connected to a plurality of networks. In general, a mobile terminal performs handover between different networks in such a manner that the mobile terminal confirms whether the mobile terminal can be connected to a network to which the mobile terminal will hand over and then receives information on neighbouring connection nodes between the different networks to implement the handover of the mobile terminal.
However, even if handover can be performed between different networks as described above, most current services are based on IPv4 and do not support IPv6 in many cases and it is difficult to support IPv6 service in IPv4 based service. A mobile terminal cannot use real-time service while moving because the existing IPv4 based mobility technology is not currently used in an actual IPv4 network. Furthermore, it is difficult to secure mobility of a mobile terminal when IP versions are different, that is, between IPv4 based service and IPv6 based service, and thus mobility should be secured in the event of handover between different networks.
Accordingly, it is required to develop technology as interim technology of IPv4 and IPv6 as the current IPv4 based communication service is evolved into IPv6 based service.
Moreover, mobility supporting technology for real-time services such as VoD and VoIP is based on IPv4, and thus the technology cannot be used in IPv6 because mobility cannot be supported. Since these real-time services are currently provided while mobility is ignored, there is a problem in the service effectiveness thereof. Therefore, development of technology capable of supporting mobility for real-time services is needed.